Enhancing energy saving and carbon footprint reduction using PCM-based heat exchanger: a COMSOL simulation approach

• Detailed study, previous work, future possibility of a heat exchanger to fulfill energy demand. • Modeling and study of novel geometry of heat exchanger using COMSOL Multiphysics • Energy storage analysis by varying geometry and boundary conditions. • Analysis of the optimum thickness of the inner copper tube. • Techno-Economic Analysis and Carbon Mitigation. The increasing energy consumption and greenhouse gas emissions are negatively affecting the environment, among which thermal comfort accounts for more than 40% of the total consumption in residential buildings. In this study, the energy storage capacity of the heat exchanger was enhanced by integrating a phase change material (PCM) (n-octadecane) for thermal energy storage. To this end, this study focuses on leveraging the high latent heat and appropriate melting point of n-octadecane for effective phase-change applications. . The geometry of the heat exchanger was also optimized to improve the liquid fraction and energy storage capacity. A COMSOL Multiphysics-based simulation model was employed to investigate and optimize the heat exchanger’s performance. The results show improved energy efficiency compared to traditional methods. For instance, a single PCM capsule (25 mm × 30 mm × 1, 000 mm) can achieve an annual CO 2 emission reduction of 13. 53 kg. Furthermore, scaling up to an array of 60 PCM tubes (each 2. 55 m long) are used in the heat exchanger leads to annual energy savings of 2, 074. 68 kWh, corresponding to reduction in CO 2, SO 2, and NO emissions of 2, 070. 53 kg, 16. 68 kg and 4. 42 kg, respectively. Economic analysis indicates the project's feasibility, with a net present value of US5. 91 and a payback period of 3. 75 years for a solar chimney integrated with PCM. In conclusion, heat exchangers based on n-octadecane PCM demonstrate significant potential as an efficient and reliable solution for thermal energy storage in building applications, contributing to a reduced carbon footprint.